If the pollsters have got this right, then the number two in the race for the Republican nomination, Rick Santorum, is in for a difficult time in today's primary in Illinois, where 69 delegates are at stake. Only a week ago, after his wins in Alabama and Mississippi, it appeared as though the state might be just within his grasp. That picture has changed dramatically in the closing stages with the two latest surveys, from Public Policy Polling and American Research group, reporting Romney leads of 15% and 14% respectively.

This follows a terrible weekend for Santorum in Puerto Rico where he put in a lot of effort and ended up with nothing. Romney won all 20 delegates at stake.

To make the case that their man is still in the race the Santorum's campaign is now disputing the overall delegate totals being reported by different parts of the US media and is saying that the race is much closer than it might appear. Thus the ABC news tally gives Romney 521 of the 1,144 required to secure the nomination with Santorum on 253. The Santorum campaign reckons that the true numbers are 435 to 311.

This is based firstly on their assumption that Arizona and Florida will eventually have to follow the party's national rules and allocate their delegates proportionally rather than winner takes all scheme. Secondly, the campaign claims that delegate tallies in three caucus states, Iowa, Missouri and Washington, should be estimated based on what is happening in the ongoing county and district conventions rather than the statewide "beauty contest" votes

Santorum's new delegate strategist John Yob, who performed a similar role for McCain in 2008, is quoting one county in Washington state which Romney won by 29% in the caucuses at the start of the month, where Santorum now has the most delegates going to the state convention where the overall make-up of the state's contingent for the national convention will be resolved.

Even if all this works out it is hard to see how Santorum can make the 1,144 total that is required in the state nominating contests that remain.